Journal of Formalized Mathematics
Volume 4, 1992
University of Bialystok
Copyright (c) 1992 Association of Mizar Users

The abstract of the Mizar article:

Connectedness Conditions Using Polygonal Arcs

by
Yatsuka Nakamura, and
Jaroslaw Kotowicz

Received August 24, 1992

MML identifier: TOPREAL4
[ Mizar article, MML identifier index ]


environ

 vocabulary EUCLID, PRE_TOPC, FINSEQ_1, RELAT_1, FUNCT_1, TOPREAL1, BOOLE,
      RELAT_2, TOPREAL2, MCART_1, METRIC_1, ARYTM_3, ARYTM_1, TARSKI, PCOMPS_1,
      SUBSET_1, TOPREAL4, FINSEQ_4, ARYTM;
 notation TARSKI, XBOOLE_0, SUBSET_1, ORDINAL1, XREAL_0, REAL_1, NAT_1,
      RELAT_1, FUNCT_1, FINSEQ_1, FINSEQ_4, STRUCT_0, PRE_TOPC, CONNSP_1,
      METRIC_1, PCOMPS_1, EUCLID, TOPREAL1, TOPREAL2;
 constructors REAL_1, NAT_1, CONNSP_1, PCOMPS_1, TOPREAL1, TOPREAL2, FINSEQ_4,
      INT_1, MEMBERED, XBOOLE_0;
 clusters SUBSET_1, FUNCT_1, PRE_TOPC, RELSET_1, STRUCT_0, EUCLID, XREAL_0,
      TOPREAL1, INT_1, XBOOLE_0, MEMBERED, ZFMISC_1;
 requirements REAL, NUMERALS, BOOLE, SUBSET, ARITHM;


begin

 reserve P,P1,P2,R for Subset of TOP-REAL 2,
         W for non empty Subset of TOP-REAL 2,
         p,p1,p2,p3,p11,p22,q,q1,q2,q3,q4 for Point of TOP-REAL 2,
         f,h for FinSequence of TOP-REAL 2,
         r for Real,
         u for Point of Euclid 2,
         n,m,i,j,k for Nat,
         x,y for set;

theorem :: TOPREAL4:1
 for D being non empty set, f being FinSequence of D, p being Element of D
  holds (f^<*p*>)/.(len f + 1) = p;

definition let P,p,q;
 pred P is_S-P_arc_joining p,q means
:: TOPREAL4:def 1
   ex f st f is_S-Seq & P = L~f & p=f/.1 & q=f/.len f;
end;

definition let P;
 attr P is being_special_polygon means
:: TOPREAL4:def 2
   ex p1,p2,P1,P2 st p1 <> p2 & p1 in P & p2 in P &
   P1 is_S-P_arc_joining p1,p2 & P2 is_S-P_arc_joining p1,p2 &
    P1 /\ P2 = {p1,p2} & P = P1 \/ P2;
  synonym P is_special_polygon;
 end;

definition let P be Subset of TOP-REAL 2;
 attr P is being_Region means
:: TOPREAL4:def 3
  P is open & P is connected;
  synonym P is_Region;
end;

theorem :: TOPREAL4:2
P is_S-P_arc_joining p,q implies P is_S-P_arc;

theorem :: TOPREAL4:3
W is_S-P_arc_joining p,q implies W is_an_arc_of p,q;

theorem :: TOPREAL4:4
W is_S-P_arc_joining p,q implies p in W & q in W;

theorem :: TOPREAL4:5
  P is_S-P_arc_joining p,q implies p<>q;

theorem :: TOPREAL4:6
  W is_special_polygon implies W is_simple_closed_curve;

theorem :: TOPREAL4:7
p`1 = q`1 & p`2 <> q`2 & p in Ball(u,r) & q in Ball(u,r) &
f =<* p,|[p`1,(p`2+q`2)/2]|,q *> implies
f is_S-Seq & f/.1 =p & f/.len f = q & L~f is_S-P_arc_joining p,q &
L~f c= Ball(u,r);

theorem :: TOPREAL4:8
p`1 <> q`1 & p`2 = q`2 & p in Ball(u,r) & q in Ball(u,r) &
f = <* p,|[(p`1+q`1)/2,p`2]|,q *> implies
f is_S-Seq & f/.1 =p & f/.len f = q & L~f is_S-P_arc_joining p,q &
L~f c= Ball(u,r);

theorem :: TOPREAL4:9
p`1 <> q`1 & p`2 <> q`2 & p in Ball(u,r) & q in Ball(u,r) &
|[p`1,q`2]| in Ball(u,r) & f =<* p,|[p`1,q`2]|,q *> implies
f is_S-Seq & f/.1 =p & f/.len f = q & L~f is_S-P_arc_joining p,q &
L~f c= Ball(u,r);

theorem :: TOPREAL4:10
p`1 <> q`1 & p`2 <> q`2 & p in Ball(u,r) & q in Ball(u,r) &
|[q`1,p`2]| in Ball(u,r) & f =<* p,|[q`1,p`2]|,q *> implies
f is_S-Seq & f/.1 =p & f/.len f = q & L~f is_S-P_arc_joining p,q &
L~f c= Ball(u,r);

theorem :: TOPREAL4:11
p <> q & p in Ball(u,r) & q in Ball(u,r) implies
ex P st P is_S-P_arc_joining p,q & P c= Ball(u,r);

theorem :: TOPREAL4:12
p<>f/.1 & (f/.1)`2 = p`2 & f is_S-Seq &
p in LSeg(f,1) & h = <* f/.1,|[((f/.1)`1+p`1)/2,(f/.1)`2]|,p *> implies
h is_S-Seq & h/.1=f/.1 & h/.len h=p & L~h is_S-P_arc_joining f/.1,p &
L~h c= L~f & L~h = L~(f|1) \/ LSeg(f/.1,p);

theorem :: TOPREAL4:13
p<>f/.1 & (f/.1)`1 = p`1 & f is_S-Seq &
p in LSeg(f,1) & h = <* f/.1,|[(f/.1)`1,((f/.1)`2+p`2)/2]|,p *> implies
h is_S-Seq & h/.1=f/.1 & h/.len h=p & L~h is_S-P_arc_joining f/.1,p &
L~h c= L~f & L~h = L~(f|1) \/ LSeg(f/.1,p);

theorem :: TOPREAL4:14
p<>f/.1 & f is_S-Seq & i in dom f & i+1 in dom f &
i>1 & p in LSeg(f,i) & p<>f/.i & p<>f/.(i+1) & h = (f|i)^<*p*> implies
h is_S-Seq & h/.1=f/.1 & h/.len h=p & L~h is_S-P_arc_joining f/.1,p &
L~h c= L~f & L~h = L~(f|i) \/ LSeg(f/.i,p);

theorem :: TOPREAL4:15
f/.2<>f/.1 & f is_S-Seq & (f/.2)`2 = (f/.1)`2 &
h = <* f/.1,|[((f/.1)`1+(f/.2)`1)/2,(f/.1)`2]|,f/.2 *> implies
h is_S-Seq & h/.1=f/.1 & h/.len h=f/.2 &
L~h is_S-P_arc_joining f/.1,f/.2 & L~h c= L~f &
L~h = L~(f|1) \/ LSeg(f/.1,f/.2) & L~h = L~(f|2) \/ LSeg(f/.2,f/.2);

theorem :: TOPREAL4:16
f/.2<>f/.1 & f is_S-Seq & (f/.2)`1 = (f/.1)`1 &
h = <* f/.1,|[(f/.1)`1,((f/.1)`2+(f/.2)`2)/2]|,f/.2 *> implies
h is_S-Seq & h/.1=f/.1 & h/.len h=f/.2 &
L~h is_S-P_arc_joining f/.1,f/.2 & L~h c= L~f &
L~h = L~(f|1) \/ LSeg(f/.1,f/.2) & L~h = L~(f|2) \/ LSeg(f/.2,f/.2);

theorem :: TOPREAL4:17
f/.i<>f/.1 & f is_S-Seq & i>2 & i in dom f & h = f|i implies
h is_S-Seq & h/.1=f/.1 & h/.len h=f/.i &
L~h is_S-P_arc_joining f/.1,f/.i &
L~h c= L~f & L~h = L~(f|i) \/ LSeg(f/.i,f/.i);

theorem :: TOPREAL4:18
p<>f/.1 & f is_S-Seq & p in LSeg(f,n) implies
  ex h st h is_S-Seq & h/.1=f/.1 & h/.len h = p &
          L~h is_S-P_arc_joining f/.1,p & L~h c= L~f &
          L~h = L~(f|n) \/ LSeg(f/.n,p);

theorem :: TOPREAL4:19
p<>f/.1 & f is_S-Seq & p in L~f implies
ex h st h is_S-Seq & h/.1=f/.1 & h/.len h = p &
        L~h is_S-P_arc_joining f/.1,p & L~h c= L~f;

theorem :: TOPREAL4:20
( p`1=(f/.len f)`1 & p`2<>(f/.len f)`2 or
  p`1<>(f/.len f)`1 & p`2=(f/.len f)`2 ) &
 not f/.1 in Ball(u,r) & f/.len f in Ball(u,r) &
 p in Ball(u,r) & f is_S-Seq &
LSeg(f/.len f,p) /\ L~f = {f/.len f} & h=f^<*p*> implies
h is_S-Seq & L~h is_S-P_arc_joining f/.1,p & L~h c= L~f \/ Ball(u,r);

theorem :: TOPREAL4:21
not f/.1 in Ball(u,r) & f/.len f in Ball(u,r) & p in Ball(u,r) &
|[p`1,(f/.len f)`2]| in Ball(u,r) & f is_S-Seq &
p`1<>(f/.len f)`1 & p`2<>(f/.len f)`2 & h=f^<*|[p`1,(f/.len f)`2]|,p*> &
(LSeg(f/.len f,|[p`1,(f/.len f)`2]|) \/
 LSeg(|[p`1,(f/.len f)`2]|,p)) /\ L~f = {f/.len f} implies
L~h is_S-P_arc_joining f/.1,p & L~h c= L~f \/ Ball(u,r);

theorem :: TOPREAL4:22
not f/.1 in Ball(u,r) & f/.len f in Ball(u,r) & p in Ball(u,r) &
|[(f/.len f)`1,p`2]| in Ball(u,r) & f is_S-Seq &
p`1<>(f/.len f)`1 & p`2<>(f/.len f)`2 & h=f^<*|[(f/.len f)`1,p`2]|,p*> &
(LSeg(f/.len f,|[(f/.len f)`1,p`2]|) \/
 LSeg(|[(f/.len f)`1,p`2]|,p)) /\ L~f = {f/.len f} implies
L~h is_S-P_arc_joining f/.1,p & L~h c= L~f \/ Ball(u,r);

theorem :: TOPREAL4:23
not f/.1 in Ball(u,r) & f/.len f in Ball(u,r) & p in Ball(u,r) &
f is_S-Seq & not p in L~f implies
ex h st L~h is_S-P_arc_joining f/.1,p & L~h c= L~f \/ Ball(u,r);

theorem :: TOPREAL4:24
for R,p,p1,p2,P,r,u st p<>p1 & P is_S-P_arc_joining p1,p2 & P c= R &
                       p in Ball(u,r) & p2 in Ball(u,r) & Ball(u,r) c= R
 ex P1 being Subset of TOP-REAL 2 st P1 is_S-P_arc_joining p1,p & P1 c= R;

 reserve P, R for Subset of TOP-REAL 2;

theorem :: TOPREAL4:25
for p st R is_Region &
P = {q: q<>p & q in R & not ex P1 being Subset of TOP-REAL 2
  st P1 is_S-P_arc_joining p,q & P1 c=R} holds P is open;

theorem :: TOPREAL4:26
R is_Region & p in R &
P = {q: q=p or ex P1 being Subset of TOP-REAL 2 st
  P1 is_S-P_arc_joining p,q & P1 c=R} implies P is open;

theorem :: TOPREAL4:27
p in R & P={q: q=p or ex P1 being Subset of TOP-REAL 2 st
  P1 is_S-P_arc_joining p,q & P1 c=R} implies P c= R;

theorem :: TOPREAL4:28
R is_Region & p in R & P={q: q=p or ex P1 be Subset of TOP-REAL 2
  st P1 is_S-P_arc_joining p,q & P1 c=R}
implies R c= P;

theorem :: TOPREAL4:29
  R is_Region & p in R & P={q: q=p or ex P1 being Subset of TOP-REAL 2 st
  P1 is_S-P_arc_joining p,q & P1 c=R} implies R = P;

theorem :: TOPREAL4:30
  R is_Region & p in R & q in R & p<>q implies
  ex P st P is_S-P_arc_joining p,q & P c=R;

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